Factors Associated with Attitudes towards Preventing Head and Neck Cancer through HPV Vaccination in Poland: A Nationwide Cross-Sectional Survey in 2021

Human papillomavirus (HPV) infection is a risk factor for head and neck cancers (HNC). HPV-related head and neck cancers are preventable through vaccination. This study aimed to assess the attitudes towards HPV vaccination among adults in Poland, with particular emphasis on preventing HPV-related HNC, as well as identifying factors associated with a willingness to vaccinate children against HPV. This cross-sectional survey was carried out in November 2021 on a nationwide, representative sample of 1082 adults in Poland. The computer-assisted web interview (CAWI) technique was used. Only 42.5% of respondents were aware that HPV infection is a sexually transmitted disease. Less than one fourth of respondents (23.8%) indicated vaccination as an HPV infection prevention method and 51.9% of respondents correctly indicated HPV vaccine-eligible populations. Only 48.1% of respondents declared positive attitudes towards HPV vaccinations and declared that they would vaccinate their child against HPV. Males (OR: 1.43, 95% CI: 1.11–1.85; p < 0.01), respondents who did not have children (OR: 1.50, 95% CI: 1.04–2.14; p < 0.05), as well as those who had received a higher education (OR: 1.43, 95% CI: 1.11–1.85; p < 0.01), had greater odds of indicating positive attitudes towards HPV vaccinations. This study revealed a low level of public awareness of HPV vaccination as a cancer prevention method in Poland.


Introduction
Human papillomavirus (HPV) is a common viral infection [1,2]. The route of HPV transmission is primarily through sexual contact (vaginal, anal, or oral sex) [1][2][3][4]. HPV can also be transmitted by less intimate skin-to-skin contact (e.g., petting) [5]. It is estimated, that approximately 75% of sexually active men and women may acquire an HPV infection, at some point in their lives [6].
Most HPV infections are asymptomatic and clear spontaneously [1,2,7]. However, some types of HPV may lead to serious diseases [7]. There are more than 200 types of HPV, of which at least 14 types are oncogenic [2]. HPV has been found to cause cancer of the cervix, anus, penis, vulva, vagina, and oropharynx [8].
We aimed to assess the attitudes towards HPV vaccinations among adults in Poland, with a particular emphasis on preventing head and neck cancers through HPV vaccination, as well as to identify factors associated with a willingness to vaccinate children against HPV.

Study Desing and Population
This cross-sectional survey was carried out in November 2021 on a nationwide, representative sample of 1082 individuals aged 18 years and over in Poland. The computerassisted web interview (CAWI) technique was used [36]. Data were collected by a specialized survey company (Nationwide Research Panel Ariadna [37]) on behalf of the research team, which provides the context of the survey.
Respondents were selected from the Nationwide Research Panel Ariadna out of >100,000 registered and verified individuals aged 18 and over. The Nationwide Research Panel Ariadna is the biggest independent nationwide research panel in Poland, widely used in nationwide, representative cross-sectional surveys [38][39][40].
A non-probability quota sampling technique was used [37]. Participants were selected based on the stratification model, including gender, age, size of domicile, and the territorial distribution within administrative regions (16 voivodeships) in Poland. The stratification model included demographic data from Statistics Poland [41].

Measures
The research tool was a questionnaire developed for the purpose of this study. Questions on head and neck cancer, HPV infection, and attitudes towards the HPV vaccine were addressed. Questions also addressed personal characteristics, including gender, age, marital status, having children, educational level, size of place of residence, occupational status, and financial status.
Self-reported knowledge about HPV infection. Respondents were asked about their awareness of HPV transmission, using the question: "How can you get infected with human papilloma virus (HPV)? Please select all that apply" with 6, mutually nonexclusive answers: by a kiss; by touching; by having sex; during natural childbirth; by having contact with the blood of an infected person; and difficult to tell/do not know. Moreover, respondents were asked about HPV infection prevention methods, using the question: "What do you think are the human papilloma virus (HPV) infection prevention methods? Please select all that apply" with 6, mutually nonexclusive answers: vaccination before the initiation of sexual contact; condom use; limiting the number of sexual partners and avoiding risky sexual behavior; other forms; infection with HPV cannot be prevented; and difficult to tell/do not know. Moreover, respondents were asked about the oncogenic potential of HPV, using the question: "What do you think are the risk factors for head and neck cancer?" with 10, mutually nonexclusive answers (including HPV infection as one of the answers [38]).
Self-reported knowledge about HPV vaccination. Respondents were asked about their knowledge of HPV vaccination recommendations (eligible groups), using the question: "In your opinion, who should be vaccinated against human papilloma virus (HPV)?" with four possible answers: girls before the initiation of sexual contact; boys before the initiation of sexual contact; boys and girls before the initiation of sexual contact; difficult to tell/do not know. Respondents who indicated "boys and girls before the initiation of sexual contact" were classified as those who were aware of the population eligible for the HPV vaccine.
Willingness to vaccinate children against HPV was defined using the question: "Would you like to vaccinate your child against human papilloma virus (HPV)?". Respondents who indicated positive attitudes toward HPV vaccination by choosing the answers: "Definitely yes" or "Rather yes" were classified as those who declared a willingness to vaccinate their children against HPV.

Statistical Analysis
The data were analyzed with SPSS v. 28 (IBM, Armonk, NY, USA). The distribution of categorical variables was shown by frequencies and proportions. Statistical testing to compare categorical variables was completed using the independent samples chi-square (χ2) test.
Associations between sociodemographic factors such as gender, age, marital status, having children, place of residence, educational level, occupational status (active-currently employed or self-employed; passive-currently unemployed/pensioner/student), selfreported financial situation as well as self-reported knowledge about the oncogenic potential of HPV (head and neck cancer risk factor), and awareness of HPV infection prevention methods were analyzed using the logistic regression analyses. Vaccination before the initiation of sexual contact, condom use, and limiting the number of sexual partners and avoiding risky sexual behavior were considered separately as dependent variables in the model. These variables were selected because they are some of the most common HPV infection prevention methods that are well described in the literature.
Additionally, similar logistic regression analyses were carried out for the associations between sociodemographic factors and attitudes towards HPV vaccination ("positive attitudes towards HPV vaccination"), as well as knowledge about HPV vaccination recommendations ("awareness of population eligible for the HPV vaccine"). In univariate logistic regression analyses, all variables were considered separately. In multivariate logistic regression analyses, all sociodemographic variables were included.
The strength of association was measured by the odds ratio (OR) and 95% confidence intervals (95% CI). The level of statistical significance was set at alpha 0.05.

Ethics
This study was performed in line with the principles expressed in the Declaration of Helsinki. The study protocol was revised and approved by the Ethics Review Board at the Central Clinical Hospital of the Ministry of the Interior and Administration in Warsaw, Warsaw, Poland (approval number 131/2021). Informed consent was obtained from all the subjects involved in the study.

Subjects' Characteristics
Completed questionnaires were received from 1082 individuals (52.6% females), aged 18-86 years (mean age 44.5 ± 16.1). Detailed characteristics of the study population is presented in Table 1.

Respondents' Knowledge about HPV Infection and HPV Vaccination
Only one third (32.5%) of respondents were aware of the oncogenic potential of HPV and indicated HPV infection as a risk factor for head and neck cancer ( Table 2). Most of the respondents indicated sex (42.5%) and contact with the blood of an infected person (42.4%) as the modes of transmission of HPV. The most identified HPV prevention methods were condom use (44.4%) and limiting the number of sexual partners and avoiding risky sexual behavior (44.4%). Less than one fourth of respondents indicated vaccination as an HPV infection prevention method. More than one third of respondents (35.1%) declared a lack of knowledge on HPV prevention methods (responses "difficult to tell" or "do not know"). Over half of the respondents (51.9%) correctly indicated that both boys and girls before the initiation of sexual contact should receive the HPV vaccine (eligible populations). Only 48.1% of respondents declared positive attitudes towards HPV vaccination and declared that they would vaccinate their child against HPV (20.5%-"definitely yes"; 27.6%-"rather yes"). Details are presented in Table 2.

Awareness of HPV Infection Prevention Methods by Sociodemographic Factors
Females compared to males more often indicated condom use (50.1% vs. 38.0%; p < 0.001) or limiting the number of sexual partners and avoiding risky sexual behavior (49.7% vs. 38.4%; p < 0.001) as a method of preventing HPV infection. The percentage of respondents who indicated vaccination before sexual initiation as a method of preventing HPV infection was significantly higher among those who lived in larger cities compared to those who lived in small cities (below 20,000 residents) or rural areas (Table 3). Respondents who had received a higher education were more aware of HPV infection prevention methods. There were no statistically significant differences in the respondents' knowledge of the HPV infection prevention methods by age, marital status, having children, occupational status, and self-reported financial situation (Table 3). Table 3. Awareness of HPV infection prevention methods by sociodemographic factors, Poland, November 2021 (n = 1082).

Attitudes towards HPV Vaccination and Knowledge about HPV Vaccination Recommendations by Sociodemographic Factors
The percentage of respondents, who correctly indicated "boys and girls before the initiation of sexual contact" as eligible for the HPV vaccine, increased with age (Table 4). Moreover, respondents who had received a higher education, those with passive occupational status, as well as those who were aware of the oncogenic potential of HPV, indicated correct populations eligible for the HPV vaccine significantly more often. Females, respondents who had a higher education, respondents with good or very good self-reported financial situation, as well as those who were aware of the oncogenic potential of HPV, more often indicated positive attitudes towards HPV vaccination. Details are presented in Table 4.

Factors Associated with Awareness of HPV Infection Prevention Methods and HPV Vaccination
The results of the univariate and multivariate regression analyses are presented in Tables 5 and 6. When adjusted for all covariables, females had higher odds of indicating that condom use (OR: 1.70, 95% CI: 1.31-2.19; p < 0.001) or limiting the number of sexual partners and avoiding risky sexual behavior (OR: 1.59, 95% CI: 1.23-2.06; p < 0.001) are the HPV infection prevention methods. Respondents aged 30-44 had higher odds of indicating that condom use is an HPV infection prevention method (OR: 1.56, 95% CI: 1.02-2.38; p < 0.05). Those respondents who lived in cities with more than 500,000 residents had higher odds of indicating that vaccination before the initiation of sexual contact (OR: 2.08, 95% CI: 1.32-3.28, p < 0.01) or condom use (OR: 1.51, 95% CI: 1.04-2.19; p < 0.05) are HPV infection prevention methods compared to those who lived in rural areas. Respondents who had a higher education had greater odds of being aware that vaccination before the initiation of sexual contact is an HPV infection prevention method (OR: 1.62, 95% CI: 1.21-2.22; p < 0.001). Respondents who were aware of the oncogenic potential of HPV (head and neck cancer risk factor) had higher odds of being aware of HPV infection prevention methods. Details are presented in Table 5. Table 5. Factors associated with awareness of HPV infection prevention methods (n = 1082).

Variable
Vaccination  Respondents who had received a higher education had higher odds of being aware of the population eligible for the HPV vaccine (OR: 1.34, 95% CI: 1.03-1.73; p < 0.05) as well as indicating positive attitudes towards HPV vaccination (OR: 1.43, 95% CI: 1.11-1.85; p < 0.01). Respondents who self-declared a rather good, good, or very good financial situation (OR: 0.69, 95% CI: 0.49-0.99; p < 0.05) or moderate financial situation (OR: 0.69, 95% CI: 0.48-0.98) had lower odds of being aware of the population eligible for the HPV vaccine (Table 6). Males (OR: 1.43, 95% CI: 1.11-1.85; p < 0.01) as well as those respondents who did not have children (OR: 1.50, 95% CI: 1.04-2.14; p < 0.05) had higher odds of indicating positive attitudes towards HPV vaccination. Respondents who lived in cities had higher odds of indicating positive attitudes towards HPV vaccination compared to those who lived in rural areas (Table 6). Respondents who were aware of the oncogenic potential of HPV (head and neck cancer risk factor) had higher odds of being aware of the population eligible for the HPV vaccine (OR: 2.56, 95% CI: 1.95-3.37; p < 0.001) as well as indicating positive attitudes towards HPV vaccination (OR: 1.95, 95% CI: 1.49-2.54; p < 0.001). Details are presented in Table 6.

Discussion
To the best of the authors' knowledge, this is the most up-to-date study on the attitudes towards preventing head and neck cancers through HPV vaccination in a representative sample of adults in Poland. This study revealed a low level of public awareness regarding HPV vaccinations. Only 42.5% of respondents were aware that HPV infection is a sexually transmitted disease and 42.4% incorrectly indicated that HPV infection is a bloodborne disease. Less than one fourth of respondents correctly indicated that HPV can be prevented through vaccination, and approximately half of respondents correctly indicated HPV vaccine-eligible populations. Approximately half of the respondents declared positive attitudes towards HPV vaccinations. Public attitudes towards preventing head and neck cancer through HPV vaccination differed by sociodemographic factors, of which the educational level was the most important factor.
According to the Polish National Cancer Registry, in 2015, 50% of newly diagnosed oropharyngeal cancers were attributed to HPV infection [42]. Despite the high burden of HPV-related cancers, in this study, only one third of respondents were aware of the oncogenic potential of HPV (head and neck cancer risk factor). There is varying knowledge even among health practitioners [32,33]. Jeruzal-Świątecka and Pietruszewska showed that more than 80% of medical students and approximately 56% of non-medical students were aware of the oncogenic potential of HPV infection, but less than 40% were aware that HPV may cause cancers other than cervical [32]. Jackowska et al. showed that 7% of ENTs, 20% of GPs, and 10% of trainees were not aware of HPV-related oropharyngeal diseases [33]. Awareness of the oncogenic potential in Poland is relatively low, which may lead to a low HPV vaccination coverage rate and may affect physicians' willingness to inform patients about the possibility of HPV vaccinations.
In this study, less than half of the respondents (42.5%) correctly indicated sexual contact as a route of HPV transmission. We observed a relatively high percentage of respondents who incorrectly believed that HPV may be transmitted through blood (42.5%), by kiss (20.5%), or by touch (7.4%). A similar phenomenon was observed by Smolarczyk et al. in a group of parents in Poland [34]. In 2018, 78.9% of parents believed that HPV may be transmitted through blood contact, 90% indicated that HPV may be transmitted by a kiss, and 13.3% by touch [34]. Awareness of HPV transmission routes is crucial to implementing preventive measures. Educational campaigns on HPV transmission routes are needed.
In this study, limiting the number of sexual partners and avoiding risky sexual behavior as well as the use of condoms (44.4%) were the most recognized HPV infection prevention methods, wherein the percentage of respondents who were aware of these methods was significantly higher among females. In the study by Smolarczyk et al.,63.3% of parents in Warsaw, Poland indicated the use of condoms as an HPV infection prevention method and 70.6% indicated limiting the number of sexual partners as an HPV prevention method [34]. The differences between our study and the study by Smolarczyk et al. may result from different populations included in the study (a representative sample of adults in Poland vs. a convenience sample of parents in Warsaw). In our study, more than one third of respondents declared a lack of knowledge about HPV infection prevention methods. Most of the educational campaigns on HPV infection in Poland were focused on HPV-related cervical cancers and were led by gynecologists, so the target population was females. A further campaign should also include the role of HPV infection in oropharyngeal diseases and should address the general population.
In this study, only one quarter of respondents indicated vaccinations as an HPV prevention method. Respondents with a higher education, those who lived in cities with more than 500,000 residents, as well as those who were aware of the oncogenic potential of HPV (head and neck cancer risk factor), were more aware of the HPV vaccine as an infection prevention method. Our findings indicate that there is a need to increase the level of knowledge about HPV vaccinations among Poles with a lower level of education, as well as those who live in rural areas. Local governments, as well as local non-governmental organizations and associations (especially in rural areas), can be involved in education on HPV vaccinations.
According to the Polish Preventive Vaccination Plan, HPV vaccination is recommended for girls and boys before sexual initiation [30]. In this study, only 51.9% of respondents correctly indicated HPV vaccine-eligible populations. There was no significant impact of gender, age, or place of residence on public awareness of HPV vaccine-eligible populations. A lack of significant differences by socioeconomic factors (except the educational level) suggests that other factors may have an impact on public awareness of HPV vaccineeligible populations. Physicians play an essential role in promoting vaccination. Most of the medical doctors in Poland support HPV vaccination [35]. However, in 2018, only 65% of gynecologists and 51.2% of pediatrists informed patients about the possibility of vaccinating their daughters against HPV [35]. We can hypothesize that physicians and their attitudes towards HPV vaccination, especially their willingness to inform patients about the possibility of vaccination, play a crucial role in promoting HPV vaccinations.
Regular monitoring of public awareness towards the HPV vaccine is an essential part of vaccination policy. Identification of public concerns and hesitant attitudes allows for the promotion of educational campaigns that build vaccine confidence. Gańczak et al. showed that between 2013-2014, 85.1% of parents of high school students from three selected high schools in Zgorzelec, Poland, declared a willingness to vaccinate their children against HPV [43]. In 2018, Smolarczyk et al. showed that 55% of parents from Warsaw, Poland, would have vaccinated their children (if the vaccination was covered by the government) [34]. In this study, less than half of the respondents (48.1%) declared that they would vaccinate their child against HPV. The differences between our study and study by Gańczak et al. [43] or Smolarczyk et al. [34] may result from different study populations, selection (representative sample vs. local, convenience sample), as well as the study year. Nevertheless, in each of the studies, the proportion of respondents who declared a willingness to vaccinate their children against HPV is multiple times higher than the real HPV vaccination coverage rate in Poland and indicates potential barriers to accessing HPV vaccinations in Poland. Logistic barriers such as the availability of vaccines, access to vaccination points, financial barriers (lack of reimbursement), as well as a lack of knowledge about HPV infection and vaccines, are considered major factors limiting the widespread implementation of HPV vaccination programs in Poland [34].
This study has practical implications for vaccination policies. The proportion of respondents who declared their willingness to vaccinate their children against HPV was five times lower than the HPV vaccination coverage rate among teenagers in Poland, which may indicate systemic barriers to receiving HPV vaccinations. Further activities are needed to ensure easy access to HPV vaccines for those individuals who intend to vaccinate their children. Organizational barriers, as well as financial barriers, are considered the most important factors [29,34]. Public health activities (e.g., full public funding of HPV vaccines and pharmacy-located HPV vaccinations) are needed to ensure easy access to HPV vaccines for those individuals who intend to vaccinate their children against HPV. Moreover, otolaryngologists should be actively involved in cancer prevention programs. The head and neck cancer burden in Poland (including HPV-related cancers) is increasing, so otolaryngologists should also educate their patients on HPV prevention methods.
Our findings suggest that there is an urgent need to conduct a nationwide information campaign on HPV infection prevention methods and the health risk of HPV-related diseases. In Poland, most educational campaigns on HPV infections were led by obstetricians or gynecologists and were addressed to females. Further educational campaigns should target all genders.
This study had several potential limitations. This study was carried out using the CAWI research method, which excludes the possibility of interaction with the respondents. Therefore, the ability to assess the competencies of the respondents, for example, whether they sufficiently understand the questions asked, is impossible. Second, we cannot exclude non-response bias. However, similar methods were used in previously published papers [38][39][40]. Moreover, questions on barriers restricting access to HPV vaccinations, as well as the potential impact of religious beliefs on attitudes towards HPV vaccinations, were not included in this study.

Conclusions
This study demonstrated the low public awareness of HPV infection prevention methods among adults in Poland. Less than one quarter of adults in Poland were aware that HPV infection can be prevented through vaccination, and only half of the Poles declared positive attitudes towards HPV vaccinations. Male gender, living in cities, and having a higher education were the most important factors associated with positive attitudes towards HPV vaccinations. The current study indicated significant gaps in the recognition of HPV vaccine-eligible populations. The presented data underscore the importance of adopting an educational campaign on HPV infection prevention methods, with particular emphasis on vaccinations. Otolaryngologists should be actively involved in the educational campaign on HPV vaccines, due to the significant burden of HPV-related head and neck cancers in Poland.  Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.